Retractable safety belts



Aug. 16, 1966 (5. BOARD ETAL RETRACTABLE SAFETY BELTS Filed Oct. 29, 1963 INVENTORJ RICHARD 6. BOARD NELSON H. SHAPIRO and S/zqow ATTORNEYS the tongue 12 of the belt.

United States Patent 3,266,842 RETRACTABLE SAFETY BELTS Richard G. Board, Bethesda, Md. (3000 Connecticut Ave., Washington, D.C.) and Nelson H. Shapiro, Hyattsville, Md. (801 Washington Bldg, Washington, D.C.)

Filed Oct. 29, 1963, Ser. No. 319,847 9 Claims. (Cl. 297-388) This invention relates to retractable safety belts, and more particularly to so-called seat belts, which are freely retractable and extensible until the belt fastener is engaged, whereupon further extension of the belt is automatically prevented. The principles of the invention may be utilized in conventional two-strap installations, but the invention is especially adapted to built-in installations supplied as original equipment by the vehicle manufacturer. It is accordingly a principal object of the invention to provide improved apparatus of the foregoing type.

Another object of the invention is to provide apparatus of the foregoing type utilizing positive metal-to-metal locking.

Another object of the invention is to provide apparatus of the foregoing type having automatic accommodations for size of person, adjustment of seat position, and changes of apparel, while preserving complete safety.

Still another object of the invention is to provide apparatus of the foregoing type which is simple and foolproof in its construction and manner of operation.

An additional object of the invention is to provide apparatus of the foregoing type which is actuated electrically but locked mechanically, thereby minimizing power drain and faulty operation due to power failure.

Briefly state, and without intent to limit the scope of the invention, a typical form of the invention utilizes the tongue of a belt fastener to actuate a mechanism for preventing extension of the belt when the tongue is engaged by a latch. When the tongue is released from the latch, the belt is retracted automatically.

The foregoing and other objects, advantages and features of the invention, and the manner in which the same are accomplished will become more readily apparent upon consideration of the following detailed description of the invention in conjunction with the accompanying drawings, which illustrate the preferred and exemplary embodiments, and wherein:

FIGURE 1 is a diagrammatic view illustrating one form of electrically actuated apparatus of the invention;

FIGURE 2 is a sectional view illustrating a latch mechanism and associated switches of the invention;

FIGURE 2A is a schematic diagram illustrating a circuit of the invention;

FIGURES 3, 4, 5 and 6 are schematic diagrams of alternative forms of circuits of the invention; and

FIGURE 7 is a diagrammatic view illustrating another form of electrically actuated apparatus of the invention.

Referring to the drawings, and initially to FIGURE 1 thereof, reference numeral 10 designates a seat belt comprising a single strap, such as a length of nylon webbing, one end of which is provided with a fastener tongue 12, such as the type conventionally employed in seat belts having metal-to-metal fasteners, and the other end of which is fixed to the arbor of a retracting reel 14A. The reel, which may be spring-wound in accordance with any of the conventional techniques, may be supported for rotation at one side of a seat 18 indicated diagrammatically in phantom lines. A latch mechanism 20 is supported at the opposite side of the seat and may comprise the usual latch elements for receiving and releasably holding For example, as will be later described in connection with FIGURE 2, the latch mechanism may be of the type having an abutment which enters an aperture in the tongue 12 and which is withdrawn by movement of a lever.

When the seat belt is not in use, the belt is wound upon the reel 14A, and the tongue 12 is located adjacent the reel at one side of the seat, as for example at the outlet of a sleeve (not shown) through which the belt passes. The user grasps the tongue 12, draws the belt across his lap, and inserts the tongue 12 into the latch mechanism 20, the belt being withdrawn from the reel 14A, which is free to turn against its normal spring bias.

In this form of the invention the belt 10 passes from retracting reel 14A past an abutment 36 located at one side of the seat 18. The abutment is shown adjacent the reel 14A, but since the reel does not partake in the belt clamping action to be described, it may be located elsewhere. On the side of the belt opposite the abutment 36 is located a cam 33 turnable about an axis 40 toward and away from the abutment 36. The cam is normally turned away from the abutment by a tension spring 42. As described in the applicants copencling application, Serial No. 313,948, filed October 4, 1963, the surface of the cam which engages the belt may be roughened and contoured so as to increase the clamping pressure in response to a pull upon the belt after the cam is initially engaged with the belt. The belt is free to be extended from the reel 14A when the tongue 12 is pulled initially and is free to be retracted by the reel when the tongue is released, as will be described more fully hereinafter.

A latch mechanism 20 for the tongue 12 is located at the side of the seat 18 opposite the cam and abutment just described. A typical mechanism is illustrated in greater detail in FIGURE 2, and includes the usual pivoting release lever 44 movable about the axis of a pin 46 which extends between the sides of a buckle shell 48 having a baseplate 50. As is well known in the seat belt art, the latch mechanism may comprise protrusions 52 adapted to enter aligned openings 54 in the tongue 12 and 56 in the baseplate 50 to hold the tongue when the tongue is inserted. The protrusions may be supported directly upon the lever 44-, but in the well known form shown they are supported upon a pair of arms 58 which are turnable about the axis of pin 46 with respect to the lever 44, so that the protrusions may be lifted when the tongue is inserted without moving the lever. The protrusions are normally biased into the openings 56 by a torsion spring 60 which also serves to bias the lever 44 to the position illustrated. While the protrusions are free to move without the lever when the tongue is inserted, they are moved by the lever to release the tongue by virtue of the engagement of the lever and the arms 58 at region 62. The specific construction of the latch mechanism is not the present invention.

In the form illustrated in FIGURES 1 and 2, the tongue 12 is utilized to control an electric circuit including a main solenoid 64 (FIGURE 1) and a locking solenoid 66. The armature 68 of the main solenoid is normally pulled upwardly by a tension spring 70, while the armature 72 of the locking solenoid 66 is normally moved to the left by a compression spring 74. Solenoid 64 has a rod 76 movable with the armature and provided with a notch 78 for reception of the end of the armature 72. Rod 76 is adapted to engage cam 38 and turn the cam to clamp the belt 10. In the position shown in FIGURE 1 neither solenoid is energized, the cam is released, and the end of armature 72 of the locking solenoid 66 engages the surface of the rod 76 but not the notch 78.

Associated with the latch mechanism of FIGURE 2 is a pair of switches 80 and 82, which may be located within the shell 48. Switch 80 is adapted to be actuated by the tongue 12, and switch 82, is adapted to be actuated by-a boss 84 fixed to the inside of the lever 44.

A typical circuit including switches 80 and 82 and solenoids 64 and 66 is shown in FIGURE 2A, the circuit being energized by a suitable source of electric power, such as a battery 86. In the form shown switch 8%) is a three-position switch having a pair of open (or inactive) positions on oppoiste sides of a closed (or active) position. Switch 82 is a two-position switch, one open, one closed. Switch 80 is normally open and is closed momentarily when the tongue is inserted into the latch mechanism but is then reopened as is passes its closed position upon full insertion of the tongue. Switch 82 normally closed but is opened when the latching lever 44 is in the position shown in FIGURE 2.

Assume that the tongue 12 is not engaged with the latch mechanism 20, solenoids 64 and 66 are de-energized and the cam 38 is released as illustrated in FIGURE 1. The user may then draw the belt across his lap and insert the tongue within the latch mechanism 20. This moves the blade of switch 86 from its norm-ally open position past its closed position to its other open position. Switch 82 is not affected, because lever 44 does not move when the tongue is inserted. FIGURE 2A illustrates the position of the switches after the tongue has been inserted as shown in FIGURE 2. The momentary closure of switch 80 is sufficient to energize solenoid 64 from battery 86, causing the solenoid to draw in its armature 68 and extend rod 76. Extension of rod 76 moves cam 38 to engage and clamp the belt against abutment 36. When the rod is extended, the end of armature 72 of the locking solenoid 66 enters notch 78 under the bias of spring 74, thereby latching the rod 76 in an extended position even though the solenoid 64 is energized only momentarily. Further extension of the seat belt is now impossible, and the belt is effectively a fixed length extending from one side of the seat across the lap of the user to the other side of the seat. Any pull upon the belt will only wedge the cam 38 more tightly against the belt and abutment 36. It will be noted that power is drawn from the battery 86 only momentarily.

If now the lever 44 is moved to release the latch mechanism, switch 82 is closed causing solenoid 66 to draw in armature 72, releasing the rod 76, which is withdrawn by spring 70, permitting the cam 38 to return to its non clamping .position under the bias of spring 42. As the tongue 12 is withdrawn from the latch mechanism, switch 80 will again close momentarily, but since the lever 44 is grasped to release the tongue, switch 82 will be closed during the momentary closure of switch 80, and there will be no locking action. Reel 14A will then retract the belt, switch 80 will return to its normally open position, and switch 82 will be re-opened upon release of lever 44.

FIGURE 3 illustrates an embodiment employing a single switch 80A in place of switches 80 and 82. Switch 80A, which is a four-position switch, may be located in the place of switch 80 in FIGURE 2. The switch is normally open with the blade in the lowermost position of FIGURE 3 and is moved to the uppermost position illustrated in FIGURE 3 upon insertion of the tongue 12. In the course of this movement locking solenoid 66 is momentarily energized, which has no effect, and then main solenoid 64 is momentarily energized, which causes extension of rod 76 and mechanical locking of the rod in extended position as described in connection with FIG- URE .2. The resultant movement of cam 38 prevents further extension of the belt.

If now the tongue is withdrawn from the latch mechanism, solenoid 64 is momentarily energized, which is of no effect, and then looking solenoid 66 is momentarily energized, withdrawing armature 72 from locking engagement with rod 76 and permitting the rod to be withdrawn by spring 70. When the tongue is fully withdrawn, switch 80A regains its normally open position.

FIGURE 4 illustrates a circuit in which the unnecessary momentary energizations described above are eliminated. This circuit employs a two-position switch B, which may be located in the position of switch 80 in FIGURE 2. The energization circuit for solenoid 64 includes a switch 88 which is open when armature 72 of solenoid 66 is in locking position and which is closed when the armature is drawn in to unlocked position. The energization circuit for solenoid 66 includes a switch which is closed when rod 76 of solenoid 64 is extended and which is opened when the rod is retracted.

FIGURE 4 illustrates the positions of the apparatus with the belt clamped after engagement of tongue 12 with its latch mechanism. When the tongue 12 is not engaged with its latch mechanism, switch 80B is closed upon the alternate position (lower contact) of FIGURE 4, switch 90 is opened and switch 88 is closed. When the tongue is inserted in the latch mechanism, switch 363 moves to the position illustrated in FIGURE 4, completing an energization circuit for solenoid 64. The solenoid extends rod 76, and armature 72 of solenoid 66 moves to lock the rod in extended position. In so moving, the armature opens switch 88, de-energizing solenoid 64. Switch 90 closed when solenoid 64 was energized. If new the tongue is withdrawn from its latch mechanism, switch 86B returns to the lower contact of FIGURE 4, completing an energization circuit for locking solenoid 66, thereby releasing .rod 76, and opening switch.90 to ale-energize the solenoid 66. The time constants of the energization circuit are chosen to ensure that solenoid 66 remains energized long enough to permit unlocking even though switch 90 breaks the energization circuit.

FIGURE 5 illustrates an alternative form of circuit in which switches 88A and 90A coresponding to switches 88 and 90 of FIGURE 4 control the energization circuits of the solenoids which move the respective switches. Switch 88A is normally closed when rod 76 is drawn into solenoid 64. Switch 90A is closed when the armature of solenoid 66 is in looking position, as illustrated in FIGURE 5. When the tongue of the belt is not inserted in the latch mechanism, switch 803 rests upon its lower contact, but since switch 90A is open, locking solenoid 66 is not energized. When the tongue is inserted, switch 863 moves to the position shown in FIG- URE 5, closing an energization circuit for solenoid 64 through normally closed switch 88A. When the solenoid is energized, rod 76 is extended, permitting armature 72 to enter the locking notch under the bias of compression spring 74. Energization of the solenoid 64 opens switch 88A, but the electrical and mechanical time constants of the solenoid circuit are chosen so that even momentary energization of solenoid 64 is sufiicient to ensure that rod 76 extends for enough for locking. When the armature 72 of solenoid 66 moves into locking position, switch 90A is closed. Thus, when the tongue is released and switch 80B closes upon its lower contact, solenoid 66 is energized to release rod 76. Again, the time constants of the energization circuit for solenoid 66 are chosen so that momentary energization is sufficient to ensure unlocking.

FIGURE 6 illustrates an alternative circuit in which one of the solenoids, in this case solenoid 64, controls both switches 88B and 96B. The operation of this circuit will be apparent from the previous description. The circuit is shown in the locked condition, and when switch 80B is moved to its alternate contact, solenoid 66 is energized to unlock the cam, closing switch 88B and opening switch 90B. Either solenoid may operate both sets of contacts.

FIGURE 7 illustrates an electrically actuated version of the invention in which a spring-wound retracting reel 14 is locked by means of a detent inserted in the serrations of end discs fixed to the arbor upon which the webbing is wound. In this case the end of rod 76A is utilized as the detent. The operating circuit may take the form of any of those described above, or any other appropriate circuit.

While preferred forms of the invention have been shown and described, it will be apparent to those skilled in the art that modifications can be made without departing from the principals and spirit of the invention, the scope of which is defined by the appended claims. For example, the latch mechanism for the tongue, the belt clamping mechanism, and/or the retracting device may be anchored directly to the seat, or to elements such as straps, or directly to the floor. Moreover, the parts may be located at the sides of individual seats or under the surface of individual or bench-type seats. Certain features of the invention may be employed with other types of belt extension-control mechanisms and other types of retracting devices. The electrical circuits may be connected to the electrical system of the vehicle or self contained. Indicator lamps may be employed to show the conditions of the various circuits. Accordingly, the foregoing embodiments are to be considered illustrative, rather than restrictive of the invention, and those modifications which come within the meaning and range of equivalency of the claims are to be included therein.

The invention claimed is:

1. A retractable seat belt comprising a retraction device, a strap connected to said retraction device for extensile and retractile movement, electrically operated means for preventing said extensile movement, said strap having a fastener at a free end thereof arranged to be grasped for extending said strap to a user-restraining position, means engaging said fastener for releasably holding said fastener when said strap is in said user-restraining position, electric supply means, and means responsive to engagement of said fastener and said fastener-holding means for m0- mentarily connecting said electrically operated means with said supply means to energize said electrically operated means and then to de-energize it as said fastener is engaged with said fastener-holding means, said electrically operated means having mechanically locking means op erative after said momentary energization for maintaining said electrically operated means effective to prevent said extensile movement of said strap.

2. The retractable seat belt of claim 1, said connecting means comprising a switch adjacent to said fastener-holding means, said switch having an inactive position on each side of at least one active position and being moved to said positions in sequence as said fastener is engaged with said fastener-holding means.

3. The retractable seat belt of claim 1, further comprising means responsive to release of said fastener from said fastener-holding means for unlocking said electrically operated means.

4. The retractable seat belt of claim 3, said unlocking means comprising another electrically operated means and means connecting it with said supply means in response to release of said fastener, said fastener-holding means having a release member, the last-mentioned connecting means comprising switch means operatively coupled to said release member.

5. The retractable seat belt of claim 3, said unlocking means comprising another electrically operated means and means momentarily connecting it with said supply means in response to release of said fastener.

6. The retractable seat belt of claim 5, each of said connecting means including switch means controlled by the associated electrically operated means.

7. The retractable seat belt of claim 5, each of said connecting means including switch means controlled by the electrically operated means associated with the other connecting means.

8. The retractable seat belt of claim 5, each of said connecting means including switch means controlled by one of said electrically operated means and arranged to permit alternate energization of said electrically operated means.

9. The retractable seat belt of claim 5, both said connecting means comprising a switch adjacent to said fastener-holding means, said switch having an inactive posi tion on each side of a pair of active positions and being moved to said positions in sequence as said fastener is engaged with said fastener-holding means, said switch having contacts at said active positions connected to said electrically operated means, respectively.

References Cited by the Examiner UNITED STATES PATENTS 2,825,581 3/1958 Knight 297-388 X 2,869,200 1/1959 Phillips et al 280 X 2,880,789 4/1959 Leibinger 297-385 X 2,883,123 4/1959 Finnigan 297388 X 3,100,669 8/1963 Monroe 297--388 3,126,227 3/1964 Bollinger 297-385 3,147,996 9/1964 Ferrara et a1. 297388 3,166,146 1/1965 Shaw 297385 X 3,172,700 3/1965 Haas 297-388 FOREIGN PATENTS 848,208 9/1960 Great Britain.

FRANK B. SHERRY, Primary Examiner.

R. B. FARLEY, Assistant Examiner. 

1. A RETRACTABLE SEAT BELT COMPRISING A RETRACTION DEVICE, A STRAP CONNECTED TO SAID RETRACTION DEVICE FOR EXTENSILE AND RETRACTILE MOVEMENT ELECTRICALLY OPERATED MEANS FOR PREVENTING SAID EXTENSILE MOVEMENT, SAID STRAP HAVING A FASTENER AT A FREE END THEREOF ARRANGED TO BE GRASPED FOR EXTENDING SAID STRAP TO A USER-RESTRAINING POSITION, MEANS ENGAGING SAID FASTENER FOR RELEASABLY HOLDING SAID FASTENER WHEN SAID STRAP IS IN SAID USER-RESTRAINING POSITION, ELECTRIC SUPPLY MEANS, AND MEANS RESPONSIVE TO ENGAGEMENT OF SAID FASTENER AND SAID FASTENER-HOLDING MEANS FOR MO- 